ABSTRACT
The Keap1-Nrf2 signalling to transcriptionally regulate antioxidant response element (ARE)-driven target genes has been accepted as key redox-sensitive pathway governing a vast variety of cellular stresses during healthy survival and disease development. Herein, we identified two nuanced isoforms α and ß of Keap1 in HepG2 cells, arising from its first and another in-frame translation starting codons, respectively. In identifying those differential expression genes monitored by Keap1α and/or Keap1ß, an unusual interaction of Keap1 with Smad2/3 was discovered by parsing transcriptome sequencing, Keap1-interacting protein profiling and relevant immunoprecipitation data. Further examination validated that Smad2/3 enable physical interaction with Keap1, as well as its isoforms α and ß, by both EDGETSD and DLG motifs in the linker regions between their MH1 and MH2 domains, such that the stability of Smad2/3 and transcriptional activity are enhanced with their prolonged half-lives and relevant signalling responses from the cytoplasmic to nuclear compartments. The activation of Smad2/3 by Keap1, Keap1α or Keap1ß was much likely contributable to a coordinative or another competitive effect of Nrf2, particularly in distinct Keap1-based cellular responses to its cognate growth factor (i.e. TGF-ß1) or redox stress (e.g. stimulated by tBHQ and DTT). Overall, this discovery presents a novel functional bridge crossing the Keap1-Nrf2 redox signalling and the TGF-ß1-Smad2/3 pathways so as to coordinately regulate the healthy growth and development.
Subject(s)
NF-E2-Related Factor 2 , Transforming Growth Factor beta1 , Kelch-Like ECH-Associated Protein 1/genetics , Kelch-Like ECH-Associated Protein 1/metabolism , Transforming Growth Factor beta1/metabolism , NF-E2-Related Factor 2/genetics , NF-E2-Related Factor 2/metabolism , Signal Transduction , Protein Isoforms/genetics , Protein Isoforms/metabolismABSTRACT
Since Nrf1 and Nrf2 are essential for regulating the lipid metabolism pathways, their dysregulation has thus been shown to be critically involved in the non-controllable inflammatory transformation into cancer. Herein, we have explored the molecular mechanisms underlying their distinct regulation of lipid metabolism, by comparatively analyzing the changes in those lipid metabolism-related genes in Nrf1α-/- and/or Nrf2-/- cell lines relative to wild-type controls. The results revealed that loss of Nrf1α leads to lipid metabolism disorders. That is, its lipid synthesis pathway was up-regulated by the JNK-Nrf2-AP1 signaling, while its lipid decomposition pathway was down-regulated by the nuclear receptor PPAR-PGC1 signaling, thereby resulting in severe accumulation of lipids as deposited in lipid droplets. By contrast, knockout of Nrf2 gave rise to decreases in lipid synthesis and uptake capacity. These demonstrate that Nrf1 and Nrf2 contribute to significant differences in the cellular lipid metabolism profiles and relevant pathological responses. Further experimental evidence unraveled that lipid deposition in Nrf1α-/- cells resulted from CD36 up-regulation by activating the PI3K-AKT-mTOR pathway, leading to abnormal activation of the inflammatory response. This was also accompanied by a series of adverse consequences, e.g., accumulation of reactive oxygen species (ROS) in Nrf1α-/- cells. Interestingly, treatment of Nrf1α-/- cells with 2-bromopalmitate (2BP) enabled the yield of lipid droplets to be strikingly alleviated, as accompanied by substantial abolishment of CD36 and critical inflammatory cytokines. Such Nrf1α-/- -led inflammatory accumulation of lipids, as well as ROS, was significantly ameliorated by 2BP. Overall, this study provides a potential strategy for cancer prevention and treatment by precision targeting of Nrf1, Nrf2 alone or both.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , NF-E2-Related Factor 1 , Humans , Liver Neoplasms/drug therapy , Liver Neoplasms/genetics , NF-E2-Related Factor 2/genetics , Palmitates , Phosphatidylinositol 3-Kinases , Reactive Oxygen Species , NF-E2-Related Factor 1/geneticsABSTRACT
The failure of the proper protein turnover in the nervous system is mainly linked to a variety of neurodegenerative disorders. Therefore, a better understanding of key protein degradation through the ubiquitin-proteasome system is critical for effective prevention and treatment of those disorders. The proteasome expression is tightly regulated by a CNC (cap'n'collar) family of transcription factors, amongst which the nuclear factor-erythroid 2-like bZIP factor 1 (NFE2L1, also known as Nrf1, with its long isoform TCF11 and short isoform LCR-F1) has been identified as an indispensable regulator of the transcriptional expression of the ubiquitin-proteasome system. However, much less is known about how the pivotal role of NFE2L1/Nrf1, as compared to its homologous NFE2L2 (also called Nrf2), is translated to its physiological and pathophysiological functions in the nervous system insomuch as to yield its proper cytoprotective effects against neurodegenerative diseases. The potential of NFE2L1 to fulfill its unique neuronal function to serve as a novel therapeutic target for neurodegenerative diseases is explored by evaluating the hitherto established preclinical and clinical studies of Alzheimer's and Parkinson's diseases. In this review, we have also showcased a group of currently available activators of NFE2L1, along with an additional putative requirement of this CNC-bZIP factor for healthy longevity based on the experimental evidence obtained from its orthologous SKN1-A in Caenorhabditis elegans.
Subject(s)
Gene Expression Regulation , Neurodegenerative Diseases , Animals , Humans , Neurodegenerative Diseases/drug therapy , Neurodegenerative Diseases/genetics , Proteasome Endopeptidase Complex/metabolism , Protein Isoforms/metabolism , Caenorhabditis elegans/genetics , Caenorhabditis elegans/metabolism , Ubiquitins/metabolism , NF-E2-Related Factor 1/geneticsABSTRACT
The study employed gas chromatography-ion mobility spectrometry to differentiate between wines undergoing spontaneous fermentation and inoculated fermentation, with aging periods of 3, 9, and 15 months. The results indicate that throughout the three aging periods, there was a notable increase in the levels of ethyl hexanoate (Monomer, M), 2-methyl butanal, ethyl octanoate (M), ethyl octanoate (Dimer, D), propyl acetate, and 3-methylbutanal in the spontaneous Italian Riesling wine (RS). Furthermore, the compounds isoamyl acetate (M), ethyl formate (D), 4-methyl-2-pentanone (M), and ethyl formate (M) demonstrated the highest concentrations at 15 months in RS, accordingly, these compounds displayed a consistent upward trend throughout the aging period. A total of 14 volatile compounds exhibited an upward trend from 3 to 15 months in the spontaneous fermentation of Petit Verdot Wine (VS). Subsequently, these compounds attained their maximum levels. Spontaneous fermentation effectively enhances the aromatic characteristics of wines, consequently improving their capacity for aging.
ABSTRACT
The essential role of protein degradation by ubiquitin-proteasome system is exerted primarily for maintaining cellular protein homeostasis. The transcriptional activation of proteasomal genes by mTORC1 signaling depends on Nrf1, but whether this process is directly via SREBP1 remains elusive. In this study, our experiment evidence revealed that Nrf1 is not a direct target of SREBP1, although both are involved in the rapamycin-responsive regulatory networks. Closely scrutinizing two distinct transcriptomic datasets unraveled no significant changes in transcriptional expression of Nrf1 and almost all proteasomal subunits in either siSREBP2-silencing cells or SREBP1-∕-MEFs, when compared to equivalent controls. However, distinct upstream signaling to Nrf1 dislocation by p97 and its processing by DDI1/2, along with downstream proteasomal expression, may be monitored by mTOR signaling, to various certain extents, depending on distinct experimental settings in different types of cells. Our further evidence has been obtained from DDI1-∕-(DDI2insC) cells, demonstrating that putative effects of mTOR on the rapamycin-responsive signaling to Nrf1 and proteasomes may also be executed partially through a DDI1/2-independent mechanism, albeit the detailed regulatory events remain to be determined.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , NF-E2-Related Factor 1 , Humans , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , Proteasome Endopeptidase Complex/metabolism , Proteolysis , TOR Serine-Threonine Kinases/genetics , TOR Serine-Threonine Kinases/metabolism , NF-E2-Related Factor 1/metabolismABSTRACT
The effects of neutral dextran concentration and molecular mass on the adhesion of endothelial cells (EC) to siliclad-covered glass surfaces were studied using interference reflection microscopy (IRM). Results indicate that close contact of the EC to the glass slides is markedly enhanced in the presence of 500 kDa dextran, with this increase reflected by both the speed of forming close contact as well as the size of the contact area. This increased adhesion is attributed to the reduction in surface concentrations of large polymers and, therefore, to the attractive forces caused by depletion interaction. Our findings suggest that depletion could play an important role in cell-cell or cell-surface interactions via accelerating and enhancing close contacts. This interaction should thus be considered in vivo and in vitro for specific potential applications, such as cell culture and cell adhesion to biomimetic surfaces. It should therefore be of particular interest in a wide range of biomedical applications.
Subject(s)
Endothelial Cells , Polymers , Dextrans/pharmacology , Cell Adhesion , Cell CommunicationABSTRACT
In this study, an innovative fabrication method called rolling-slitting forming, which forms ultra-thin diamond blades, was presented for the first time. Furthermore, the feasibility of the rolling-slitting forming method when applied to silicon carbide wafer dicing blades was investigated; moreover, the cold-pressing blade samples were manufactured through the conventional process under the same sintering conditions to compare and analyze the manufacturing efficiency, organization and performance. The results show that the new method achieves high-precision and low-thickness dicing blades through continuous production without molds-with the thinnest blades being 0.048 mm thick. Furthermore, the rolling-slitting blade has a unique multiporous heat-conductive matrix structure and in-situ generated amorphous pyrolytic carbon, which can reduce the dicing resistance and contribute to a better cutting quality. In addition, the effects of the dicing parameters on SiC were investigated by using indications of spindle current, dicing chipping size and kerf width during the high dicing process. For a dicing depth of 0.2 mm, the ideal performance of dicing SiC with an ultra-thin blade was achieved at a spindle speed of 22,000 rpm and a feed rate of 5 mm/s. This research provides a new idea for the manufacturing of dicing blades, which can satisfy the demand for ultra-narrow dicing streets of high integration of ICs.
ABSTRACT
METHODS: From January 2015 to January 2021, auricular reconstruction was performed in 38 adult patients (39 ears) of congenital microtia based on autologous costal cartilage. The whole procedure was divided into 2 stages: stage I, the individualized framework carved with autologous costal cartilage was inserted into subcutaneous pocket in the mastoid region; then, the earlobe was transposed backward; and stage II, ear elevation, harvesting the retroauricular fascial flap to cover the support scaffold and closing the defect with free skin graft, was performed. RESULTS: All patients successfully underwent ear reconstruction. The follow-up time ranged from 3 months to 3 years. Infection occurred in 1 patient. The ear frameworks were partially broken at the helix in 4 cases. Retroauricular graft skin survival was poor in 1 patient. Retroauricular hypertrophic scars occurred in 2 cases. Bad projection of the reconstructed ear occurred in 1 case. Totally 38 patients were satisfied with the results. CONCLUSIONS: According to the physiological characteristics of the costal cartilage and skin soft tissues of adult patients, improvements are made to details based on the Nagata's method, so that the adult patients with microtia can obtain satisfactory surgical results.
Subject(s)
Congenital Microtia , Plastic Surgery Procedures , Adult , Cartilage/transplantation , Congenital Microtia/surgery , Ear, External/abnormalities , Ear, External/surgery , Humans , Plastic Surgery Procedures/methods , Surgical Flaps/surgeryABSTRACT
To defend against a vast variety of challenges in oxygenated environments, all life forms have evolutionally established a set of antioxidants, detoxification, and cytoprotective systems during natural selection and adaptive survival, to maintain cell redox homeostasis and organ integrity in the healthy development and growth. Such antioxidant defense systems are predominantly regulated by two key transcription factors Nrf1 and Nrf2, but the underlying mechanism(s) for their coordinated redox control remains elusive. Here, we found that loss of full-length Nrf1 led to a dramatic increase in reactive oxygen species (ROS) and oxidative damages in Nrf1α-∕- cells, and this increase was not eliminated by drastic elevation of Nrf2, even though the antioxidant systems were also substantially enhanced by hyperactive Nrf2. Further studies revealed that the increased ROS production in Nrf1α-∕- resulted from a striking impairment in the mitochondrial oxidative respiratory chain and its gene expression regulated by nuclear respiratory factors, called αPalNRF1 and GABPNRF2. In addition to the antioxidant capacity of cells, glycolysis was greatly augmented by aberrantly-elevated Nrf2, so to partially relieve the cellular energy demands, but aggravate its mitochondrial stress. The generation of ROS was also differentially regulated by Nrf1 and Nrf2 through miR-195 and/or mIR-497-mediated UCP2 pathway. Consequently, the epithelial-mesenchymal transformation (EMT) of Nrf1α-∕- cells was activated by putative ROS-stimulated signaling via MAPK, HIF1α, NF-ÆB, PI3K and AKT, all players involved in cancer development and progression. Taken together, it is inferable that Nrf1 acts as a potent integrator of redox regulation by multi-hierarchical networks.
ABSTRACT
Spatter is an inherent, unpreventable, and undesired phenomenon in laser powder bed fusion (L-PBF) additive manufacturing. Spatter behavior has an intrinsic correlation with the forming quality in L-PBF because it leads to metallurgical defects and the degradation of mechanical properties. This impact becomes more severe in the fabrication of large-sized parts during the multi-laser L-PBF process. Therefore, investigations of spatter generation and countermeasures have become more urgent. Although much research has provided insights into the melt pool, microstructure, and mechanical property, reviews of spatter in L-PBF are still limited. This work reviews the literature on the in situ detection, generation, effects, and countermeasures of spatter in L-PBF. It is expected to pave the way towards a novel generation of highly efficient and intelligent L-PBF systems.
ABSTRACT
In current study, nano-Fe3O4@activated coke enhanced bio-system (FEBS) under limited-oxygen condition was applied for efficient treatment of aromatic organics in coal pyrolysis wastewater. Metagenomic analyses revealed functional microbiome linkages and mechanism involved in aromatic ring-cleavage. Based on biodegradation efficiency in different reactors, FEBS supplementation conferred the best organic removal (avg. 92.29%). It also showed a remarkable advantage in biodegradability maintenance (>40%) over control reactors. Metagenomics profiling revealed the degradation processes were driven by Fe3O4 redox reactions and microbial biofilm, while the suspended sludge was the principal force for aromatic mineralization. Based on the analysis of functional species and genes, most bacteria cleaved the benzene ring preferably through the aerobic pathways, mediated by catechol 1, 2-dioxygenase, catechol 2, 3-dioxygenase and protocatechuate 3, 4-dioxygenase (66-84%). Ecological network showed that Comamonas testosterone-centered microbiome and Azotobacter linked to the nitrogen (N)-heterocyclic ring-cleavage. Network linkage further demonstrated that Alicycliphilus and Acidovorax were the key tone taxa involved in benzene ring-cleavage. Finally, combined with analysis of degradation products, bacteria degraded N-heterocyclic ring containing organic aromatic compounds (quinoline) mainly through anaerobic processes, whereas cleavage of benzene ring preferred aerobic pathways. The enriched functional species were the primary reason for the enhanced biodegradation in FEBS.
Subject(s)
Coke , Water Purification , Biodegradation, Environmental , Coal , Metagenomics , Pyrolysis , Waste Disposal, Fluid , WastewaterABSTRACT
The coal pyrolysis wastewater (CPW) contributed to aquatic environment contamination with amount of aromatic pollutants, and the research on joint toxicity of the mixture of aromatic compounds was vital for environmental protection. By using Tetrahymena thermophile as non-target organism, the joint toxicity of typical nonpolar narcotics and polar narcotics in CPW was investigated. The results demonstrated that the nonpolar narcotics exerted chronic and reversible toxicity by hydrophobicity-based membrane perturbation, while polar narcotics performed acute toxicity by irreversible damage of cells. As the most hydrophobic nonpolar narcotics, indole and naphthalene caused the highest joint toxicity in 24 h with the lowest EC50mix (24.93 mg/L). For phenolic compounds, the combination of p-cresol and p-nitrophenol also showed the top toxicity (EC50mix = 10.9 mg/L) with relation to high hydrophobicity, and the joint toxicity was obviously stronger and more acute than that of nonpolar narcotics. Furthermore, by studying the joint toxicity of nonpolar narcotics and polar narcotics, the hydrophobicity-based membrane perturbation was the first step of toxicity effects, and afterwards the acute toxicity induced by electrophilic polar substituents of phenols dominated joint toxicity afterwards. This toxicity investigation was critical for understanding universal and specific effects of CPW to aquatic organisms.
Subject(s)
Coal , Pyrolysis , Tetrahymena/drug effects , Wastewater/toxicity , Water Pollutants, Chemical/toxicity , Indoles/toxicity , Naphthalenes/toxicity , Narcotics/toxicity , Phenols/toxicityABSTRACT
To investigate the role of electroactive biofilms for enhanced phenolic degradation, lignite activated coke (LAC) and MAC were used as carriers in moving-bed biofilm reactor (MBBR) for CPW treatment. In contrast to activated sludge (AS) reactor, the carriers improved degradation performance of MBBR. Although two MBBRs exerted similar degradation capacity with over 92% of COD and 93% phenols removal under the highest phenolics concentration (500â¯mg/L), the effluent of MAC-based MBBR remained higher biodegradability (BOD5/CODâ¯=â¯0.34 vs 0.18) than that of LAC-based MBBR. Metagenomic analysis revealed that electroactive biofilms determined phenolic degradation of MAC-based MBBR. Primarily, Geobacter (17.33%) started Fe redox cycle on biofilms and developed syntrophy with Syntrophorhabdus (6.47%), which fermented phenols into easily biodegradable substrates. Subsequently, Ignavibacterium (3.38% to 2.52%) and Acidovorax (0.46% to 8.83%) conducted biological electricity from electroactive biofilms to suspended sludge. They synergized with dominated genus in suspended sludge, Alicycliphilus (19.56%) that accounted for phenolic oxidation and nitrate reduction. Consequently, the significantly advantage of Geobater and Syntrophorhabdus was the keystone reason for superior biodegradability maintenance of MAC-based MBBR.
Subject(s)
Coke , Wastewater , Biofilms , Bioreactors , Coal , Magnetic Phenomena , Phenols , Pyrolysis , Sewage , Waste Disposal, FluidABSTRACT
Powdered activated carbon (PAC), lignite activated coke (LAC) and Fe-C carriers were applied to enhance CBFBRs to degrade targeted phenolics. In start-up stage, PAC and LAC equipped CBFBRs with higher environment adaptability and phenolic degradation capacity for phenol (>96%), p-cresol (>91%) and 3, 5-dimethylphenol (>84%) in comparison to Fe-C carrier. In recovery stage, the superior performance was also identified for CBFBRs in basis of PAC and LAC than Fe-C-based reactor. However, the Fe-C carrier assisted CBFBR with more stable degradation performance under impact loading. By comparing microbiomes, significantly enriched Brachymonas (54.80%-68.81%) in CBFBRs exerted primary role for phenolic degradation, and positively contributed to microbial network. Meanwhile, Geobacter in Fe-C-based reactor induced excellent impact resistance by enhancing interspecific electron transfer among microbes. Furthermore, the investigation on functional genes related to phenolic degradation revealed that anaerobic pathway accounted for demethylation procedure, while aerobic pathways dominated the phenolic ring-cleavage process.
Subject(s)
Microbiota , Wastewater , Bioreactors , Coal , Phenols , Pyrolysis , Waste Disposal, FluidABSTRACT
Mixotrophic nitrate removal in wastewater from coal pyrolysis was achieved in microbial electrolysis cell with iron anode (iron-MEC). The effect of voltage, iron anode and conductivity were investigated. The effluent TN concentration was 8.35 ± 1.94 mg/L in iron-MEC when the conductivity of the wastewater was adjusted to 3.97 ± 0.08 mS/cm, which was lower than that in no-treated reactor. The increase of current density, which was resulted from the elevation of conductivity, promoted the iron corrosion and Fe2+ ion generation. Therefore, more Fe2+ ion was utilized by nitrate reducing ferrous oxidation bacteria (NRFOB) used to reduce nitrate. The microbial community analysis demonstrated that NRFOB, including Acidovorax and Bradyrhizobium, possessed a higher abundance in iron-MEC. The enrichment of Geobacter in iron-MEC might imply that the part of Fe(III) produced by ferrous oxidation was reduced by Geobacter, which established an iron cycle. Moreover, the production of N2O was decreased by the formation of Fe2+ ion.
ABSTRACT
Flavonoids are key determinants of grape quality and wine color. Grapevines growing in alkaline soil are prone to manganese deficiency, which can decrease the contents of secondary metabolites, including flavonoids. We determined the effects of a foliar Mn treatment (MnSO4·H2O) of Cabernet Sauvignon grapevines (V. vinifera L.) growing in alkaline soil on the flavonoid contents in grape skin, and the quality of wine. The Mn treatments were applied in 2017 and 2018, and tended to increase the grape sugars, berry weight, and the contents of phenolic compounds from veraison until harvest. The Mn treatments increased the amounts of acetylated, methylated, and total anthocyanins, as well as the total flavonol contents in grape berry skin at harvest. The wines prepared from these grapes had a higher color intensity than those prepared from grapes from control vines. Foliar-applied MnSO4·H2O can promote flavonoid biosynthesis in grape berries, and improve the color of wine.
Subject(s)
Agriculture/methods , Flavonoids/metabolism , Manganese Compounds/pharmacology , Sulfates/pharmacology , Vitis/drug effects , Wine/analysis , Anthocyanins/analysis , Anthocyanins/metabolism , China , Color , Flavonoids/analysis , Flavonols/analysis , Flavonols/metabolism , Fruit/drug effects , Fruit/metabolism , Phenols/analysis , Phenols/metabolism , Plant Leaves , Soil/chemistry , Vitis/metabolismABSTRACT
By regulating the extraction solvent and alkali in pretreatment, two carbon-based MBBRs were compared in pilot-scale to synchronously remove phenols and ammonia of coal pyrolysis wastewater (CPW) under fluctuant phenols-ammonia loadings. It revealed that lignite activated coke (LAC)-based MBBR performed more stable with phenols increasing (250-550â¯mg/L), and reached higher tolerance limit to ammonia (>320â¯mg/L) than activated carbon (AC)-based MBBR under fluctuant ammonia loadings. During the phenols-ammonia synchronous removal process, the LAC provided the firm basis for shock resistance due to superior resilient adsorption capacity, enhanced sludge property and microbial cooperation. Furthermore, microbial analysis revealed that the strengthened collaboration between archaea and facultative bacteria played the primary role in phenols-ammonia synchronous degradation. Specifically, the heterotrophic bacteria consumed phenols-ammonia by partial nitrification process and ammonia assimilation, following by denitrifying process to further eliminate phenols. The multifunctional Comamonas was the critical genus participating in all procedures.
Subject(s)
Ammonia , Wastewater , Biofilms , Bioreactors , Carbon , Coal , Phenols , Pyrolysis , Waste Disposal, FluidABSTRACT
The coupling of bioelectrochemical system with the biological denitrification process (R1) was constructed for nitrate removal in coal pyrolysis wastewater (CPW) and the effect of low-intensity direct current electric field was investigated. Compared with control reactor (R2), the total nitrogen (TN) removal efficiency in R1 at the optimized voltage of 0.9â¯V was 94.20⯱â¯2.14%, which was 14.42% higher than that in R2. The biofilm on the cathode of R1 enhanced the nitrate reducing, however, nitrite was only reduced by bacteria in suspended activated sludge, which was confirmed by cyclic voltammetry measurement (CV). Microbial community network analysis revealed that exoelectrogenic bacteria of Pseudomonas was enriched on the anode of R1, and the "small world", including Zoogloea, Pseudomonas and Arenimonas, was established under the stimulation of voltage. Therefore, Pseudomonas transferred electron to anode, and Arenimonas could utilize electron from anode to reduce nitrate, which enhanced TN removal in R1.
Subject(s)
Nitrogen , Wastewater , Bioreactors , Coal , Denitrification , PyrolysisABSTRACT
The purpose of this study is to investigate the enhancement of polycaprolactone (PCL) on total nitrogen (TN) removal of coal pyrolysis wastewater (CPW) with low COD to nitrogen ratio by partial nitrification-denitrification bioprocess (PNDB) in one single reactor. With the innovative combination of PCL and PNDB, the TN removal efficiency in the experimental reactor (signed as R1) was 10.21% higher than control reactor (R2). Nitrite accumulation percentage (NAP) in R1 was 82.02%, which was 17.49% higher than R2 at the dissolved oxygen (DO) concentration of 0.9-1.5 mg/L, for the reason that the extra DO was consumed by PCL biodegradation at the aerobic period. Gel permeation chromatography (GPC) results demonstrated that organics with the molecular weight of 185 Da, which could serve as additional carbon sources for denitrifiers, were generated during the PCL hydrolysis process at the anoxic period. PCL was hydrolyzed by extracellular enzymes with the break of the ester bond which was confirmed by FT-IR spectrometer. Microbial community analysis revealed that Ferruginibacter was the dominant hydrolysis bacteria in R1. Nitrosomonas were the main ammonium-oxidizing bacteria (AOB) and Hyphomicrobium were the denitrifiers in this study.